misterious banging from underneath now powerloss? you ent having much in the way of luck fella are u. 
Ha, it never rains... this is after the other problem I had (must update the thread) with the secondary air pump and hoses

As it happens these two things aren't really that much of a worry; hardly carry passengers and the power loss is reasonably rare, and only in first. Other than that it's running lovely

The TB was recently cleaned out (< 1 yr), so I'll have a check over the turbo piping. I had 17705 a while back but that seemed to be to do with the secondary air that's been recently fixed and hasn't come back since.
Cheers gents.